Furnace



J. H. ROACH. FURNACE.

ILED NOV- 2 Patented July 13,- 1920.

3 SHEETS-SHEET 1- J. H. ROACH.

FURNACE.

APPLICATION FILED NOV.27, I917.

Patented July 13, 1920.

3 SHEETS-SHEET 2.

J. H. ROACH.

FURNACE.

APPLICATION FILED NOV-27, 1917.

1,846, 464. Patented Jill 13, 1920.

3 sHEETs-sHEET s.

FURNACE.

Specification of Letters .Patent.

Patented July 13, ll2..

application filed November 27, 191?. Serial No. 204,245.

To all whom it may concern Be it known that l, Josnrrr H. Roach, a citizen of the United State's, residing at Philadelphia, Philadelphia county, and State of Pennsylvania, have invented and discovered certain new and useful lrnprovements in Furnaces, of which the following is a specification.

My said invention relates to underfeed stolrer and forced draft furnaces and to the grate bars therefor per 86, and consistsin the combinations and arrangements of ele- Inents hereinafter described and particularly set forth in the accompanying claims.

The invention has for itspurpose to provide a grate bar of the stepped type, formed trough-shaped, or inverted llshaped, in cross section and having internal tins, or flanged portions, reinforcing the stepped members whereby tolurnish supports for the steps on which the coal rests, and for the further purpose of increasing radiation, or carrying 01? the heat, which is greatest at these places in the fire place. [also a grate bar in which the chamber is "formed into two separate air spaces having a constricted communicating passageway disposed to direct the air blast from one of said spaces, which is at a higher pressure, to that portion of the other chamber which is at a lower pressure and thereby'to add slightly more pressure to the air issuing from the twyers at which the greatest combustion talzes place.

it further purpose is to provide a furnace structure having independently controlled forced draft members below the grate, cominunicating respectively with separate air spaces termed in the grate bars, to the end that either or both of the air spaces in said grate bars will receive the forced draitt from one only, or both of the forced draft chain bers.

Another object of the invention consists in providing a channeled or chambered grate bar having a dividing web forming two separate air spaces and which web 15 constructed in a manner that will allow the air space on one side of web to re ceive a small portion of the air delivered to the s race on the other side of the web and thereliy' permit a much lower static pres; sure to be carried under certain portions of the grate and thus conserve the life of the furnace structure and increase its efficiency.

The inventionis disclosed by way of illustration in the accompanying drawings wherein:

Figure 1 is a longitudinal View of one part of the grate bar,

Fig. 2, a transverse sectional view of Fig. 1 taken on the line 22 thereof,

Fig. 3, a similar view taken on the line 33 on Fig. 1,

Fig. 4, a sectional view of a detail taken on the line M on Figpl,

Fig. 5 is a transve se sectional view taken through a portion of an underteed Stoker furnace,

Fig. 6, a longitudinal view oi? one part of a modified form of grate bar,

Fig. ,7, a transverse sectional view talren on the line 88 of Fig. 6, and

8 is a similar view to Fig. 7 showing the grate bar constructed each in one piece.

Referring to the construction in further detail and wherein like reference characters indicate corresponding parts in the different views shown, the grate bar consists of a hollow structure formed on two similar parts 25, and assembled in a longitudinal plane as shown, although it will be understood, ol' coursethat the grate bar constructed with a plurality of steps 26, respectively spaced in a manner to torrn twyer openings 27, and the several twyer openings oi each grate bar are disposed substantially horizontal to direct the forced draft from the air chambers beneath the grate on to the fuel bed supported by the res )ective steps after the usual manner.

r plurality of tins or web portions 28 are formed integrally with each half of the grate bar and immediately beneath and in supporting relation to the step portions thereoi for the purpose of furnishing a sub stantial support to the steps on which the coal rests, and more particularly for the purpose of carrying off the heat which is greatest at these places in tuel bed.

Each bar of the "ate is thither provided with a tinnsverse web portion or baille 29 that disposed near to and diagonally of the notch 18 formed on the lower edge of the grate bar and said notches are adapted till to be engaged and operated by the oscillating shaft 15 of the stoker mechanism, (see Fig. 3). The dividing web or baffle 29 provides a duct or constricted passage giving intercommunication between the two air chambers into which the grate bar is divided by the partition web 29.

The two air chambers of the grate bar are located respectively immediately over and communicate with the central and side air chambers beneath the grate and into which the forced draft is delivered from the blower. It will be understood, of course, that reference is here made to only one side of the furnace, as illustrated in Fig. 5. The passage 30 between the grate bar chambers is so disposed that it directs the air blast from the chamber 20, where it is highest in the grate to the chamber 13 and takes the air from said chamber 13 and delivers the same to the first two twyer openings as indicated by the arrows. The purpose of this arrangement is to add slightly more pressure to the air delivered at this region inasmuch as the combustion is substantially at a. maximum in the fuel bed lying between the first five or six twyers on either side of the retort 11 (see Fig.

Referring to the furnace construction shown in Fig. 5, 6 designates a suitable fireplace constructed of fire brick, or other material, and on which the grate structure is erected. Said structure consists of suitable supports 7 on which the walls 8 and 9 are mounted, the wall 9 dividing the grate structure in zones or compartments through which the forced draft is admitted and contolled by suitable sliding valve mechanisms 10 as shown.

The stoker mechanism consists of a retort 11 and a coal pusher 12, and for a more detailed description of thme features of the furnace reference may be had to the co-pending application for U. S. Patent, bearing the Serial l lo. 176,240, dated June 21, 191i, and on which construction the present arrangement is proposed as an im provement.

A plurality of grate bars 13 are mounted on the grate structure 8 and the side wall of the retort 11, andv the alternate bars of the grate are adapted. to be reciprocated through the operation of the stolrer mechanism. The grate bars intermediate said movable bars are stationary and secured in an approved manner, and the usual pair 0 dumping grates 14: (one be ing shown} re pivotally mounted at the opposite outer ends of the grate bars.

The means for operating the movable grate bars from the stoker mechanism C011" sists of a rocker sl aft 15 mounted to oscillate in the journal bearing 16 formed at the upper end of the retort wall 11, and said shaft is constructed with a flange or web portion 17 engaging within the notch 18 formed in the lower edges of themovable grate bars up on one side of the retort in such manner that said grate bars are reciprocated when theshaft oscillates.

The grate bar shown in Fig. 6 consists of a hollow structure formed on two similar parts and united along a longitudinal medial plane although it will be understood, of course, that the grate bar ma be made in one piece as shown on Fig. 9.- ach grate bar is provided with a transverse web portion on bafiie. 19 that is disposed immediately over the partition 9 and flange portion 17 of the rocker shaft 15, and said web 19 with the flange 17 and partition 9 will form a virtually continuous partitioning wall or barrier that will divide the forced draft admitted into the fire place.

The forced draft entering the chamber 20 on one side of the web 19 in each grate bar issues through the ducts 21 provided at the inner end or head of the grate bar, and through these ducts the forced draft passes into the heaviest part of the fuel bed, 2". 6., directly above the retort 11. The dividing web on bafiie 19 provides a duct or constricted passage 22 that enters into the air space between the walls 8 and 9 of the supporting structure, andby this arrangement of the air will pass into the lower or outer portion of the grate bar. This provision will enable to be maintained the same static pressure in the retort Zone as the initial pressure, but the small portion of the air which passes beneath and around the dividing webs 10 of grate bars will allow a much lower static pressure to be maintained under the grate bars at those portions most distant from the retort. The reason for this lower static pressure is due to the constricted passageQQ and it will be further noted that the converse to the foregoing is true. Thus air may be passed from the outer air spaces ofthe grate bars into the inner spaces 20 thereof, all depending upon which of the controlling valves 1-0 is open or closed.

Tn the construction shown in Fig. 6 the grate bar embodies practically the same fpatures as disclosed by the grate bar in rig. 5 with the exception that the web or baffle 23 is onsiderably shorter and does not have any appreciable deflecting effect on the air.

Tt is obvious that those skilled in the art may vary the details of construction and arrangement of parts without departing from the spirit of my invention, and there fore T tures except as may be required by the claims.

Having thus described my invention what i do not wish to be limited-to such feaand means to reciprocate the bars without interfering with the constricted passages.

2; A grate for forced draft furnaces comprising a plurality of reciprocatably mounted grate bars, a partition dividing the supporting structure into separate air intake conduits, co-acting members carried by the bars forming a constricted passage by way of the barstructures between the conduits, and a rocking section, formed in the said partition and adapted to reciprocate the bars without interfering with the constricted passages.

3, A grate for forced draft furnaces comprising a plurality of reciprocatably mounted grate bars, a partition dividing the supporting structure into separate air intake conduits, co-acting members carried by the bars forming a constricted passage by way of the bar structure between the conduits, and means to reciprocate the bars without interfering with the constricted passages, said bars being provided with twyer openings in connection with the several conduits.

4. A grate for forced draft furnaces comprising a plurality of reciprocatably mounted grate bars, a partition dividing the supporting structure into separate intake conduits, co-acting members carried by the bars forming a constricted passage by way of the bar structures between the conduits, and means to reciprocate the bars without interfering with the constricted passages, said bars being provided with groups of twyer openings, each group in connection with dif ferent conduits.

, 5. A grate for forced draft furnaces comprising a plurality of reciprocatably mounted grate bars, a partition dividing the supporting structure into separate air intake conduit-s, co-acting members carried by the bars forminga constricted passage by way of the bar structure between the conduits, and a rocking section formed in said partition adapted to reciprocate the bars without interfering with the constricted passages, said bars being provided with groups of twyer openings, each group in communication with different conduits.

In witness whereof, I have hereunto set my hand and seal at Philadelphia, Pennsylvania this 8th day of October, A. D. nineteen hundred and seventeen. r

JOSEPH H. ROACH. [11. s.]

Witnesses:

RALPH B. EVANS, CHARLES J. MCDERMOTT. 

